Buggy code:
public void clear ( int index , boolean all ) { } void clear ( int hItem , TVITEM tvItem ) { } public void clearAll ( boolean all ) { } void clearAll ( int hItem , TVITEM tvItem , boolean all ) { } int CompareFunc ( int lParam1 , int lParam2 , int lParamSort ) { } public Point computeSize ( int wHint , int hHint , boolean changed ) { } void createHandle ( ) { } void createHeaderToolTips ( ) { } void createItem ( TreeColumn column , int index ) { } void createItem ( TreeItem item , int hParent , int hInsertAfter , int hItem ) { } void createItemToolTips ( ) { } void createParent ( ) { } void createWidget ( ) { } int defaultBackground ( ) { } void deregister ( ) { } void deselect ( int hItem , TVITEM tvItem , int hIgnoreItem ) { } public void deselect ( TreeItem item ) { } public void deselectAll ( ) { } void destroyItem ( TreeColumn column ) { } void destroyItem ( TreeItem item , int hItem ) { } void enableDrag ( boolean enabled ) { } void enableWidget ( boolean enabled ) { } int findIndex ( int hFirstItem , int hItem ) { } Widget findItem ( int hItem ) { } int findItem ( int hFirstItem , int index ) { } TreeItem getFocusItem ( ) { } public int getGridLineWidth ( ) { } public int getHeaderHeight ( ) { } public boolean getHeaderVisible ( ) { } Point getImageSize ( ) { } int getBottomItem ( ) { } public TreeColumn getColumn ( int index ) { } public int getColumnCount ( ) { } public int [ ] getColumnOrder ( ) { } public TreeColumn [ ] getColumns ( ) { } public TreeItem getItem ( int index ) { } TreeItem getItem ( NMTVCUSTOMDRAW nmcd ) { } public TreeItem getItem ( Point point ) { } public int getItemCount ( ) { } int getItemCount ( int hItem ) { } public int getItemHeight ( ) { } public TreeItem [ ] getItems ( ) { } TreeItem [ ] getItems ( int hTreeItem ) { } public boolean getLinesVisible ( ) { } int getNextSelection ( int hItem , TVITEM tvItem ) { } public TreeItem getParentItem ( ) { } int getSelection ( int hItem , TVITEM tvItem , TreeItem [ ] selection , int index , int count , boolean bigSelection , boolean all ) { } public TreeItem [ ] getSelection ( ) { } public int getSelectionCount ( ) { } public TreeColumn getSortColumn ( ) { } int getSortColumnPixel ( ) { } public int getSortDirection ( ) { } public TreeItem getTopItem ( ) { } int imageIndex ( Image image , int index ) { } int imageIndexHeader ( Image image ) { } public int indexOf ( TreeColumn column ) { } public int indexOf ( TreeItem item ) { } boolean isItemSelected ( NMTVCUSTOMDRAW nmcd ) { } void redrawSelection ( ) { } void register ( ) { } void releaseItem ( int hItem , TVITEM tvItem , boolean release ) { } void releaseItems ( int hItem , TVITEM tvItem ) { } void releaseHandle ( ) { } void releaseChildren ( boolean destroy ) { } void releaseWidget ( ) { } public void removeAll ( ) { } public void removeSelectionListener ( SelectionListener listener ) { } public void removeTreeListener ( TreeListener listener ) { } public void setInsertMark ( TreeItem item , boolean before ) { } public void setItemCount ( int count ) { } void setItemCount ( int count , int hParent , int hItem ) { } void setItemHeight ( int itemHeight ) { } public void setLinesVisible ( boolean show ) { } int scrolledHandle ( ) { if ( ( hwndHeader ) == 0 ) return handle ; int count = ( ( int ) ( OS . SendMessage ( hwndHeader , HDM_GETITEMCOUNT , 0 , 0 ) ) ) ; <START_BUG> return count == 0 ? handle : hwndParent ; <END_BUG> } void select ( int hItem , TVITEM tvItem ) { } public void select ( TreeItem item ) { } public void selectAll ( ) { } void setBackgroundImage ( int hBitmap ) { } void setBackgroundPixel ( int pixel ) { } void setCursor ( ) { } public void setColumnOrder ( int [ ] order ) { } void setCheckboxImageList ( ) { } public void setFont ( Font font ) { } void setForegroundPixel ( int pixel ) { } public void setHeaderVisible ( boolean show ) { } public void setRedraw ( boolean redraw ) { } void setScrollWidth ( ) { } void setScrollWidth ( int width ) { } void setSelection ( int hItem , TVITEM tvItem , TreeItem [ ] selection ) { } public void setSelection ( TreeItem item ) { } public void setSelection ( TreeItem [ ] items ) { } public void setSortColumn ( TreeColumn column ) { } public void setSortDirection ( int direction ) { } public void setTopItem ( TreeItem item ) { } void showItem ( int hItem ) { } public void showColumn ( TreeColumn column ) { } public void showItem ( TreeItem item ) { } public void showSelection ( ) { } void sort ( ) { } void sort ( int hParent , boolean all ) { } void subclass ( ) { } String toolTipText ( NMTTDISPINFO hdr ) { } int topHandle ( ) { } void updateFullSelection ( ) { } void updateHeaderToolTips ( ) { } void updateImageList ( ) { } void updateImages ( ) { } void updateScrollBar ( ) { } void unsubclass ( ) { } int widgetStyle ( ) { }

Fix:
return ( count == 0 ) && ( ( scrollWidth ) == 0 ) ? handle : hwndParent ;